Genlocking VHS to Betacam?

[lordsmurf]

Quote:

Originally Posted by Alessandro Machi

explained to me by a JVC tech.

I think the JVC tech was confused.

Quite a few ancient TBCs would need calibration of those values, and the "proc amp" wasn't actually a proc amp at all, but a self-calibration tool. But equally many didn't have the calibration options, at least not externally accessible.

[Alessandro Machi]

To clarify, the origins of the term Time Base Stabilizer was the late 90's and was associated with a JVC S-VHS machine called the EDIT Deck, which was designed to have a high speed search function and a built in Time Base Stabilizer and was half the price of a BRS series machine. However, the picture quality was noticeably less because there was no settable digital noise reduction card. The C in TBC stands for correction, or, perhaps correctable. S in Time Base Stabilizer stands for the stabilizing of the video signal, which was the primary purpose of a Time Base unit. JVC probably made a point of clarifying the difference possibly because Panasonic was erroneously calling some of their TB's, TBC's, when they were actually TBS's. For instance, the 1980, it if has no external control panel for set-up, hue, chroma, or brightness, is actually a TBS that was been misidentified by Panasonic.

[latreche34]

I don't think TBC is unique to JVC, So it doesn't matter how a JVC technician called it, TBC's were made earlier by Ampex for the quad machine 2" tape and the only function they did was to correct timing, They had other boards for chroma and luma and they did not call them TBC. So clearly the technician did not know what he is talking about or you miss understood him.

[Shakedown St.]

Quote:

Originally Posted by Alessandro Machi

There is an advance sync function on the unit so you can feed some type of black burst signal to both the 7350 and the betacam sp as a way to lock them together. However, if you can find an external TBC for the 7350 and then send that signal in via the S-Video connection to the betacam sp deck, that may be your best option.

That is awesome info! I believe my Sony SVO-5800 has that option as well after reading in the manual. I can see on the rear of the 7350 it has "Ext Sync In" which is exactly what I'm looking for. On the Sony 5800 it's called "Reference Video In". Have to learn how to use those.

The 7350 from reading around it doesn't have TBC/TBS or video DNR. The 1980 has both. However the 7350 would be the perfect scenario for feeding into a Betacam. That would make an interesting project. Of course at this point in time it seems that the 7350 would need a major overhaul considering it's age. The Sony decks are indestructible and why I am so reluctant to sell mine but I think I will be as it cannot play EP/LP tapes.

Quote:

Originally Posted by Alessandro Machi

The 7350 actually worked off of RS-232 I think it was called? I had a one of a kind special box made that would convert the RS-232 to RS-422 and was able to lock up 6 hour VHS and S-VHS tapes to my betacam sp. Sure was trippy. I had to do a 10 second pre-roll so the RS-422 controller could lock the two together before the edit point occurred.

I'm not seeing any RS-232 ports on the back of the 7350 from images online. The 7750 does. I'm seeing RCA/BNC and S-Video, and a weird remote input on the units for recording. If you recall do you remember how you worked with RS-232? I would love to do that myself.

Quote:

Originally Posted by hodgey

The AG7350 (or at least the PAL version) does not handle EP tapes properly, playing them at SP speed.

Quote:

Originally Posted by hodgey

On the simpler AG-7350 at least it basically plays LP tapes at SP speed, so it plays too fast giving chipmunk sound and a distorted image (a bit like when ffwding).

In older threads throughout the forum above when the 7350 was brought up I was reading, it was mentioned that it does not play extended play tapes at the correct speed? Perhaps they were only referring to long play. It sounds like you didn't experience this with EP.

[Alessandro Machi]

The 7350 requires an external TBC if one wants to optimize/straighten the picture before inputing it to the Betacam SP machine. I used a Fortel Super Pro TBC back in the day. It did a pretty decent job and had S-Video in and out. Internal fan design was kind of weak so it could heat up. I assume in the past 30 years there might be a better version for the 7350. The connector on the back of the unit can be converted to RS-422. I had a company called Adrienne Electronics make one for me. I don't know if they ever made another one but if they are still around they would know how to make a connection box that would then convert the signal to RS-422. It might be expensive however.

The old 2 inch decks most likely allowed the engineer to "correct" the signal, that is why it is called a Time Base Corrector. When the four basic signals cannot be manually adjusted, the correct term is time base stabilizer. https://www.adorama.com/jvsan50u.html. Just because Panasonic may have misrepresented their 1980 time base stabilizer doesn't mean they have precedence over JVC, which correctly differentiates between Time Base Corrector and Time Base Stabilizer. https://www.adorama.com/jvsan50u.html

JVC, Grass Valley, Snell, all use the word Time Base Stabilizer for Time Base units that do not have a way for a person to manually adjust basic video signals. This Snell / Grass Valley Manual mentions Time Base Stabilizer six different times. https://wwwapps.grassvalley.com/docs..._Operation.pdf

The Sony UVW's used Time Base Stabilizers, however, if one purchase the TBC remote, then they could access hue, chroma, brightness and set-up levels. Sony calls their internal TB's, TBS. Maybe that is the secret sauce here. if the TB is internal, it is a Time Base Stabilizer, if the TB has external access, then it is called a TBC. https://www.avgear.com/product/sony-...yer-for-parts/

[lordsmurf]

Not exactly.

1. TBS may be a non-jargon (or obfuscated jargon) synonym on some uses. Because stabilize/correct is essentially duplicate verbiage in layman usage. Bad translation may have had a role here.

2. Again, proc amp has nothing to do with TBC. TBC is for line timing correction -- not adjusting luma, chroma, IRE/pedestal. Completely separate processes, almost no overlap.

3. It's very rare to type in a phrase in Google, and ... nothing. "time base stabilizer" yields almost no results, aside from (mostly) your own participation in various places (Quora, etc). In fact, at least once, Google replied "Did you mean time base corrector ?"

4. I did see this on the BM forums (BlackMagic, not bowel movement, though the former often does cause the latter): "Sony UVW-1200 deck has TBS (Time Base Stabilizer) which is not exactly the same as TBC, and locks SYNC and SC to the external reference signal". That's neither TBC nor genlock. That's some sort of special something for that narrow/niche hardware usage.

[Alessandro Machi]

i just gave you three links to places that use Time Base Stabilizer that have nothing to do with me. If there is no external correction that can be made by a human, then it is a Time Base Stabilizer, as in stabilizing the picture. Otherwise, there would have to be a new term for TBC's that actually give one external control over the proc amps and if such a name exists, please share it. Why would TBC cover units that allow external control over various signals, aka correction, and also cover units that do not provide external control. Those are two different types of signal control. if you want to claim that TBC is the all encompassing name, then provide two names below it that depict internal control, and external control, then at least a logic tree has been created.

[lordsmurf]

Yes, but those links don't define what TBS actually means.

- First you claimed that TBC must have proc amp, but the links don't support that.
- Then you claimed that all TBC are actually TBS, but the links don't support that.
- Now you're claiming that TBC must have manual human control of timing, but the links don't support that.

I've been doing video for decades, and I'd never heard the term TBS. The reason is obvious to me: I didn't use those old JVC BR or Sony editing decks, and was unaware of the obscure tech contained in them.

TBCs literally do as the name suggests: correct timing (time base), and on the axis/vector it's designed for.

The problem here is that TBC is a wide term. You have line, field, and frame, and each is different. Furthermore, you actually have frame TBC, and frame sync TBC (and non-TBC frame synchronizers). The effectiveness of the TBC depends on multiple factors, and is why you can have both consumer-source TBCs and pro-source TBCs.

Buffers, instructions, and programmed expected signal ingest are all variables that determine how a TBC reacts. Lots of chips, lots of 1's and 0's, make this determination on what it can do. Make not mistake: all are TBCs. (*Except items that aren't, such as "copy removers" like Grex and Sima toys.)

And if you want a framesync TBC with use-adjusted proc amp, here you go: DataVdeo TBC-3000, AVT-8710.

More details: http://www.digitalfaq.com/forum/myth...html#post34131

This is why general rules exist:
- frame: rackmount TBCs almost always bad for consumer videotapes like VHS
- frame: Cypress and DataVideo usually good -- except flawed-chip Cypress, or EOL DataVideo (5000-type gen)
- frame: avoid "also has TBC" devices like mixers
- line: JVC/Panasonic S-VHS VCRs usually best, safe
- line: avoid "also has TBC" devices like DV converters and DVD recording, as it's often BS

[hodgey]

Interesting that the NTSC version of the AG7350 support SLP. The PAL ones are SP only. As far as I know share much of the video ICs with the prosumer SVHS-decks NV-FS100 (PAL) and AG1960 (NTSC), but the mechanism and servo parts are completely different, so maybe that helps with SLP playback too? They use individual servo motors for the tape reels instead of them being driven by a belt from the capstan motor like on most consumer vcrs, which presumably allows more fine control and quick response for seeking and such. I know seeking with the jog/shuttle dial is very smooth in comparison with consumer decks. The PAL one can give very good quality on SP tapes at least, but I've had some issues with the one we have here so never fully managed to compare it properly.

It seems to usually have come with a 34p remote control board, but panasonic made an optional RS-232 board with 25-pin d-sub connectors on it too which can replace it (ag-IA232TC). The remote output seems pretty basic too though, so it would probably not be terribly complicated for someone with engineering experience to diy a serial adapter for it.

Quote:

Originally Posted by lordsmurf

2. Again, proc amp has nothing to do with TBC. TBC is for line timing correction -- not adjusting luma, chroma, IRE/pedestal. Completely separate processes, almost no overlap.

A TBC (for a heterodyne VCR at least) had to decode and separate the luma and two chroma components, and digitize the signal in any case before stabilizing, so it made a lot of sense to combine it with video adjustment (which outside of very basic level adjustment requires separating the different components of the video signal to be done properly.). Even the TBCs in the panasonic AG1980P other VCRs typically feature some adjustments under the hood, they were just internal PCB trimpots, or, on later ICs set digitally, even if there wasn't some user control for it.

Whatever the correct term was, JVC used the term time-base corrector on their prosumer vcr and camcorders which didn't feature user level adjustments.

This early patent uses both "time base correction" and "time base stabilization" so I guess the terms have always been used a bit interchangeably.

[Alessandro Machi]

I've pretty much said the same thing all the way through. If the TB is internal and has no adjustment parameter for basic video signals, it is a TBS. If the TB has accessible adjustable dials for color, hue, set-up and brightness, then it is a time base "corrector".
I would suggest the top of the definition tree would be frame synchronizer, then below it would be two branches, one would be a time base corrector in which a person can adjust various video picture elements, and the other one would be a TBS, a time base stabilizer, such as is in the Sony Betacam SP UVW series. One can "break out" a TBS and make it a TBC if an external piece of equipment can be connected to the internals of the UVW decks so that various signals can be adjusted.

TBS's can be TBC's with the proper break out boxes. I have used such break out boxes for UVW's. The JVC BRS 525, 622 and 822 units all have built in TBC's because there are actual knobs and dials to adjust various picture parameters, but one can also get a break out box as well.

The PVW sony's had internal TBC's with a break out box, but if the TBC external box connector is disconnected when the unit is on, it actually burns out a component and the break out box won't work until the burned out part has been repaired.

In each instance, If a human being has access to actual knobs and dials to make actual picture adjustments to a video signal, the unit has a TBC, if the unit does not have the adjustments readily available without needing a break out box, it is a TBS.

If 50hz creates tape speeds that travel almost 17% slower than 60hz, the 7350 and its full size video heads probably could not scan a six hour recording playing at a slower speed. Even with 60hz, the six hour mode on a 7350 can only play back picture as it won't read the HI-FI track even if one is on the tape.

[lordsmurf]

Quote:

Originally Posted by lordsmurf

2. Again, proc amp has nothing to do with TBC.
Completely separate processes, almost no overlap.

Quote:

Originally Posted by hodgey

A TBC (for a heterodyne VCR at least) had to decode and separate the luma and two chroma components, and digitize the signal in any case before stabilizing, so it made a lot of sense to combine it with video adjustment

Almost.

Quote:

This early patent uses both "time base correction" and "time base stabilization" so I guess the terms have always been used a bit interchangeably.

As suspected, synonym, with TBC being the jargon term.

[latreche34]

Chroma and luma use level and phase adjustment not timing, So calling those adjustments TBC is flat out wrong, So TBC or TBS both refer to HBI and VBI signal timing not chroma and luma levels. Having said that lets just stick to TBC because it is more common.

Quote:

Originally Posted by hodgey View Post
A TBC (for a heterodyne VCR at least) had to decode and separate the luma and two chroma components, and digitize the signal in any case before stabilizing, so it made a lot of sense to combine it with video adjustment

Only if using composite for external TBCs, Using S-Video the signals are already separated. Line TBC I assume works out of the Y/C demodulator inside the VCR.

[Shakedown St.]

Quote:

Originally Posted by hodgey

Interesting that the NTSC version of the AG7350 support SLP. The PAL ones are SP only. As far as I know share much of the video ICs with the prosumer SVHS-decks NV-FS100 (PAL) and AG1960 (NTSC), but the mechanism and servo parts are completely different, so maybe that helps with SLP playback too?

That is very odd. I guess that means there is an extra head and if so, does that have a negative effect on the video capabilities for SP speed? In other words it's not optimized for SP? Also shopping and asking around, I noticed the PAL version of the 7350 can play NTSC tapes, but the NTSC version cannot play PAL? Interesting.

Quote:

Originally Posted by hodgey

It seems to usually have come with a 34p remote control board, but panasonic made an optional RS-232 board with 25-pin d-sub connectors on it too which can replace it (ag-IA232TC). The remote output seems pretty basic too though, so it would probably not be terribly complicated for someone with engineering experience to diy a serial adapter for it.

Another interesting note. Most of them I see have 34p connections so looks like that was a rare option. So I would need a 34p to RS-422 adapter if possible.

-- merged --

Now this is from an older thread.

Quote:

Originally Posted by Eric-Jan

@johnysh I bet you did not try the SONY SVO-5800P with the component video output board add in.... would be the perfect combination with the Intensity Shuttle, because of the stable video signal you get with component video output.
....and yes, VHS will look beatiful on the CRT you have, like already said, it all depends how you want to watch, on a big progressive HDMi monitor or a small interlaced CRT monitor (RGB?)
and the Sony SVO-5800 being a PAL model, using it with poor resolution NTSC tapes... is also not much of use, i hope you have PAL VHS tapes to capture.... you did not mention this.
Using the Intensity Shuttle only for it's composite or s-video inputs.... any other capture device will do also.

He mentioned that the signal coming out of the components was clean enough to be picked up by a modern capture card. I wonder if I would be better off running component into Betacam and that would produce a more stable signal that could work without using a TBC.

-- merged --

I listened to all of your recommendations and tried hooking up a generic VCR to the Betacam.

I can report a positive that the Betcam TBC controls responded to s-vid feed coming from the other VCR and noise reduction. I have video, chroma, set up, and hue adjustments. The Sony SVO-5800 TBC controls are a little nicer and more responsive, but to my amazement it's working and the setup cost $100. Apparently the Betacam tape mechanism works but I'll never need to use it unless I start collecting Betacam.

However the image does roll like others have said, so I've since purchased a VCR with external sync feature. I'm purchasing a blackburst generator. This way I can run the feed out of a Betacam to a capture device without dropped frames, and get the professional controls of a pro VCR while being able to run LP and SLP tapes out of any cheap VCR. Great alternative to finding a 1980/1970 out there. It does not matter if the Betacam tape mechanism does not work. Studios are dumping them like hot cakes for pennies on the dollar for the what they originally cost new.

I will report back my final thoughts when/if I get the image to stop rolling. I also have not tried running component out of the Sony 5800 to see if it gives me a stable enough signal for Betacam to like. I have to recap my Panasonic 7350 before I can start using it.

Full res: https://flic.kr/p/2m6gBh1

[latreche34]

There is a BNC connector on the back of most Betacam machines called Ref. video, Try connecting the composite output of your VHS VCR to it and see if it picks up the sync pulses while capturing from the S-Video out of the same VHS VCR, If it works and gets rid of the rolling it saves you from getting a sync generator.

[Shakedown St.]

Quote:

Originally Posted by latreche34

There is a BNC connector on the back of most Betacam machines called Ref. video, Try connecting the composite output of your VHS VCR to it and see if it picks up the sync pulses while capturing from the S-Video out of the same VHS VCR, If it works and gets rid of the rolling it saves you from getting a sync generator.

I'm back from trying that. Nope, still rolling. Anxiously awaiting my Horita in the mail.

On a second note folks, I've had more time messing around with the TBC. I now may say I like the controls on the Betacam better than the Sony SVO-5800. They are very responsive. It was hard to tell the first time with the image rolling but when I pause it you can very well see it working.

The Hue changes color. Video changes brightness. Chroma changes color intensity. It went from a black and white image to very colorful. This will come in handy in dealing with oversaturated tapes. Then Set Up appears to be changing the contrast. I can't really test the noise reduction without a still image. If I can get it to stop rolling this would be a great setup.

[latreche34]

If the proc amp works it doesn't mean the line TBC is working in the passthrough mode, They are two separate circuits, The only way to be able to tell is if it straighten the lines, Play a tape in your VCR that has bright vertical lines with dark surrounding such as door frames, poles ..etc. If the lines become more straight than they were when TBC is turned on then you know it's working.

[Shakedown St.]

Quote:

Originally Posted by latreche34

If the proc amp works it doesn't mean the line TBC is working in the passthrough mode, They are two separate circuits, The only way to be able to tell is if it straighten the lines, Play a tape in your VCR that has bright vertical lines with dark surrounding such as door frames, poles ..etc. If the lines become more straight than they were when TBC is turned on then you know it's working.

I may have been mistaken. You mention line TBC. I'm really looking to see if frame TBC is working so my capture device can record a clean signal without dropped frames.

I believe this model does not have line TBC but it could be the other way around.

[hodgey]

When messing with the PVW-2800 at least I never found any way to avoid rolling with vcrs that did not feature externa sync input. The PVW-2800 could be locked to "itself" by looping one of the composite outs to the sync input, but it didn't stop the rolling. The only setup that didn't roll was when both the AG7350 and betacam were locked to the same signal (which could be the internal one in the betacam deck.) Trying to lock the betacam deck to the video output of the vcr didn't seem to work well, from what I remember it caused a lot of jitter and such. Even with the 7350 locked the image could sometimes move around a bit when there was instability. It did seem to result in a stable output signal though.

[latreche34]

Well that indicates that the Betacam deck does not have a frame/field TBC or at least it doesn't work in passthrough mode, You would never have frame roll with an active frame TBC. I was under the impression that we are talking line TBC here.

[Shakedown St.]

Quote:

Originally Posted by latreche34

Well that indicates that the Betacam deck does not have a frame/field TBC or at least it doesn't work in passthrough mode, You would never have frame roll with an active frame TBC. I was under the impression that we are talking line TBC here.

I'm going to carefully read through the manual tonight. If all else fails, it could be a useful external proc control and possibly make line corrections that could come in handy paired with my Pan 7350. Although I was hoping by what I read it would stabilize frames as well for digital capture.

*It should also be known I'm using an upscaler @1080P so I can view it on my flat screen television. I no longer own an analog television. Not sure if that would change test results.

It does mention that it has TBC. The control knobs are even labeled "TBC controls". It could be referencing line TBC though and I was mistaken. Going to run more tests tonight. It could have both line and frame or only one. Even more than that, it could mean that proc is working in pass through but TBC only works with tapes playing like you say. Workflow will go as followed.

First test: I'm going to hook up my Blackmagic HDMI 1080P capture card and see what happens. If frame TBC is activated and there are no dropped frames then it should be able to record a signal. If not, then it will be blacked out and disabled from recording.

Second test: Will be feeding digital component out of my SVO-5800 and see if it stabilizes the image. The Betacam deck also has digital component output that could be useful. Unfortunately proc controls and TBC are disabled in pass-through on the SVO-5800.

Third test: I will run evidence of line correction when I can get it to stop rolling.

"The PVW-2800P is provided with a built-in TBC (Time Base Corrector) as standard. A superior quality output video is obtained directly from the PVW-2800P, with no additional time base correction required. Advanced high quality digital dropout compensation also ensures consistent picture performance. The Sony PVW-2800 has a built in time base corrector that you cannot bypass. All Sony Beta VTRs (BVW series, PVW series, UVW series) have built in time base correctors."

-- merged --

I forgot to add, is there a way to tell when digitizing if you don't have a frame TBC activated? I've never attempted digitizing tapes before but I have a Blackmagic HDMI 1080P capture card at 60FPS.

The intent of the test will be to purposely try to get skipped frames and black outs to determine whether TBC is engaged or not. Digital capture cards want a clean signal. I will be using an S-Video to HDMI adapter upscaler. I'm not sure if this will give an accurate test.

Based on responses in this thread, the fact that its rolling I have my doubts. However the Betacam manual says it has digital dropout compensation. I'm not exactly sure what that implies.